Europeans are bracing for a major diplomatic showdown after triggering a UN mechanism known as snapback that could reimpose international sanctions on Iran, a move Tehran has warned could escalate the nuclear crisis.
"It's a scenario we have frankly tried to avoid," a French diplomat said. "Yes, there is a risk of escalation. We thought long and hard about that risk."
France, Germany and the UK have accused Iran of breaching a nuclear deal. Late August marked the last possible deadline for the trio − known as the E3 − to reinstate sanctions on Iran, before the deal lapses in October.
Both sides have blamed each other for escalating the situation, with Iran accusing Europe of giving diplomatic cover to an Israeli and US bombing campaign in June that killed more than 1,000 Iranians.
Last-ditch negotiations
They now have 30 days for last-ditch negotiations. Europeans want Iran to account for hundreds of kilograms of uranium enriched at 60 per cent, which Tehran says is impossible to locate because it has been buried by US strikes.
They have also demanded better co-operation with UN nuclear watchdog the International Atomic Energy Agency and direct talks with the US.

"We have made it very clear to the Iranians that their interest is not in escalation but in using these 30 days to avoid the reintroduction of sanctions," the French source said. "We are very keen on this."
By triggering snapback before the end of August, the E3 are acting ahead of Russia assuming the rotating presidency of the UN Security Council in October. It's seen as a move that would reduce Moscow’s ability to delay or block the process, as the presidency allows control over the council’s agenda and discussions.
Russia, an Iranian ally that is a permanent member of the security council, has circulated a draft resolution viewed as an attempt to water down the E3 snapback mechanism. E3 members France and the UK are also permanent members of the council.
Moscow’s initial draft resolution proposed a six-month extension of the Iran nuclear deal − the Joint Comprehensive Plan of Action − and UN resolution 2231 until April 18, 2026, with the option of a further extension.
The draft also sought to suspend for the extension period any substantive council discussions related to the agreement’s implementation.
Moscow and Beijing subsequently removed the clause suspending council discussions in the latest version of the draft due to opposition from European members of the council.
The final days of the 30-day count down will coincide with the UN General Assembly's high-level week that is attended by ministers and heads of states. There will likely be intense diplomatic activity to avoid, one last time, the re-establishment of sanctions.
If talks collapse, Europeans expect Iran to react in one of several ways, based on statements made by Iranian politicians.
First, Iran may inch closer to withdrawing from the non-proliferation treaty, a landmark 1970 agreement which aims to prevent the spread of nuclear weapons.
Highly escalatory
In June, after Israel launched a surprise attack against its nuclear facilities, Iran's Parliament drafted a law to withdraw from the Nuclear Non-proliferation Treaty. So far, no vote has taken place.
The gold standard 1970s NPT both sought to control the numbers of countries with nuclear arms while allowing the spread of atomic technologies across more nations.
Withdrawal would mean Iran is no longer subject to inspections by the IAEA and potentially allow Tehran to develop nuclear weapons capabilities. Iran insists its current programme is peaceful, despite enriching uranium far above civilian levels.
Exiting the NPT would be viewed as highly escalatory by the E3, the US and Israel - the only country in the Middle East to have the nuclear bomb, though it has never acknowledged it.
That is why, according to the French diplomat, the option remains unlikely. "Parliament may green light a bill that raises the threat to withdraw without actually doing it," they said.
Other, less aggressive, options are on the table, including reduced co-operation with IAEA inspectors, who were allowed this week to return to Iran for the first time since the 12-day war. In what appeared to be a show of good faith, Iran allowed them to visit Bushehr nuclear plant. However, the E3 have little interest in Bushehr, which is the only civilian nuclear power plant that is fuelled by Russian imported enriched uranium.
Third, Iran could stop engaging with Europeans entirely. On July 20, Iran's Foreign Minister Abbas Araghchi said in a letter to UN Secretary General Antonio Guterres that the E3 does not have any "legal, political and moral standing to invoke the mechanisms of the JCPOA and UN Resolution 2231."
Enabling strikes
While the E3 did not participate in the attacks, Mr Araghchi blamed them for enabling strikes through diplomatic posturing. After the attacks, French President Emmanuel Macron said the US strikes "had no legality" though France "shared the goal of not allowing Iran to obtain a nuclear weapon".
Such accusations could surface again, if Israel or the US attack after snapback is triggered. Iranians have pointed at the timing of a recent E3-led censure vote against Iran at the IAEA board. The 35-nation board found Iran in breach of its NPT obligations on June 12. The next day, Israel launched strikes against nuclear facilities, ballistic missile factories and military commanders.
At his last in-person meeting with E3 counterparts in Geneva, Mr Araghchi had left saying he was ready to continue to talk to Europeans. The meeting, however, was shortly followed by the US attacks, with US President Donald Trump describing the E3's diplomatic efforts as unhelpful.
Europeans are often dismissed as offering no more than a weaker, less unified version of US diplomacy - a sore point which they reject. "If one day there are negotiations to lift sanctions on Iran again, we will be obliged to be around the table, whereas if we had let it [snapback mechanism] expire, we would have been completely out of the game." the French diplomat said.